Guerrier is the only player in the field yet to drop a shot after adding a 65 to his opening 68 to be 9 under par, a total later matched by joint overnight leader Bjerregaard, who returned a 68 in windy conditions.
Ryan Evans, who was the other overnight leader, had four bogeys in a round of 69 to slip a shot behind the top two.
English compatriot Steven Brown was level.
French golfer Mike Lorenzo-Vera was another stroke back after a superb 64, the lowest score of the week at Verdura Golf Club.
Guerrier regained his playing privileges via the Challenge Tour last season and is already on course for his best season on the European Tour.
“I made no bogeys, so in these conditions, in two rounds, to make no bogeys is really good,” Guerrier said. “I come from La Rochelle, where it’s very windy, so I think it helped me a lot.”