His opening goal was sublime, the subsequent misses less so.
In a contest that should have been dead and buried long before, County came good with Melvin de Leeuw's clincher late in a game that boiled over in anger amid Jim Goodwin's latest controversy.
The Dingwall team might have paid a hefty price for the wastefulness of Arquin and a number of team-mates, but victory took Derek Adams' team ninth, a point above the relegation play-off spot but with what may prove a crucial game in hand.
St Mirren, spirited though they were, left it too long to find their stride and slipped two places into that dreaded 11th-place slot.
For Arquin, the French-born Martinique internationalist on loan from Notts County, there was recognition of his mixed impact on the match. "I am happy to have scored, but the win was the most important thing," said the 25-year-old, who has three goals from five games.
While Arquin's eye was out on two occasions, St Mirren perhaps had Marian Kello to thank for long preserving the match as a contest.
The Slovakian goalkeeper's finest moment was a one-two save from Jordan Slew and Arquin, which showcased his razor-sharp reactions. "The St Mirren goalkeeper made some really good saves, of course. When he made the double save in the second half I thought it might not be our day," Arquin said.
"It is a team game, and I was very happy to lay the ball to Melvin for the winner. I won the ball and went one-on-one with the defender, looked up and saw my partner in the box.
"It is not about me proving myself. I am just glad to be at a good club, with good players and a good manager. The fans are very good as well. It was a very important win when you look at the league table."
The earthy Goodwin, who these days seems to face flak wherever he goes, had escaped punishment after a clattering challenge with County's Filip Kiss in the first half.
Anger already fomented in the County technical area boiled over later in the game as substitute De Leeuw and Goodwin clashed heads and tumbled to deck in pain.
Derek Adams and Danny Lennon were both sent to the stands after fiery exchanges, although it was hard to tell whether clumsiness or malice had been behind the two Goodwin incidents. The managers were inevitably split on party lines.
Notably, the defender himself left the field concussed, while De Leeuw stayed on to win the match.
Earlier, County defender Yann Songo'o had missed a couple of chances in front of goal in the first 20 minutes, before Arquin's looping header beat Kello seven minutes before the break.
County's inability to kill off the game fed St Mirren's enthusiasm and John McGinn netted superbly after slicing across the edge of the box to power a shot high past Mark Brown.
With the hosts' missed opportunities by this stage piled high, De Leeuw's calm stab past Kello late on was met with an outpouring of joy and relief among the County support.
It was a bitter pill to swallow for the goalkeeper, who was also quick to defend Goodwin. "Jim's reputation seems to be going against him - everyone is against him," Kello said.
"He tried to win the ball with a header, he knocked the guy and all the crowd went crazy. It was just unfortunate. Probably he had a dizzy view because of concussion when County scored."
Kello did not need any reminder of the perilous position St Mirren are in after five straight defeats. "We are really disappointed. Did we deserve that?" he asked.
"We started well and after that we had a spell where we were just kicking the ball and we dropped off a bit. In the second half, we were up for it again but it was not enough.
"I thought after I made a double save it could be a turning point, but it wasn't to be. After we scored I thought we were the team pushing forward to score a second, but County got one break and we were 2-1 down.
"My saves mean nothing at the end of the game. It was another punch in the stomach and we are in a real problem situation now. We need to turn it around and try to push harder to work on our defensive situation."