Cornish, 27, had been scheduled to meet another Englishman, Sam Sexton of Norwich, in only the second-ever British title eliminator featuring a Scot, but the former Commonwealth champion has been forced to withdraw after suffering a back injury.
The Highlander's manager, Tommy Gilmour, stressed that the bout is subject to British Boxing Board of Control approval as a final eliminator but he is not anticipating any objections.
"Lewison is the Southern Area champion, which is effectively almost half of Britain, so I do not envisage the Board having a problem sanctioning the bout," he said. "Lewison topped the bill on the final St Andrew's show of the season in June when he stopped Kreso Bogdanovic of Croatia in the second round and he is a big lump of a man and a powerful hitter who could prove even tougher than Sexton.
"I could have put Gary in with another European but the big fellow is champing at the bit to earn a shot at the British title. This will be, without doubt, the toughest fight of his career, but Gary is up for it. He has had a lot of good sparring with the likes of Tyson Fury and the American Eddie Chambers, who are also big men, and training has gone well."
Only one Scottish heavyweight has fought a British title eliminator previously, in 1949, when Dundee's Ken Shaw lost out to Freddie Mills in London. But Cornish will make history as the first Scot to contest a title eliminator in his homeland.
Cornish has a perfect record of 18 wins, 10 by KO, while 32-year-old Lewison has lost twice in 13 contests after coming to the sport late, in 2009.
Paisley light-middleweight Kris Carslaw, 29, will share top billing in another British title eliminator against Edinburgh's John Thain.
Tickets priced £40, £60 and £100, for ringside, are available by contacting 0141 810 5700.