wtsmg,
The short answer is you'll have the same chance as anyone else in Canada, with the right to work, a valid ATPL, and who also meet all the other requirements AC wants to see.
You might get a couple extra "points" for having flown an A320, but it won't do anything to your seniority, nor will it guarantee you'll be back on the 320. You're just as likely to end up on any of their other machines as cruise relief as you are an FO position. It depends on what they need on the day you pull your number and what that number allows you to hold.