You won't be able to bid for an upgrade on an AC codeshare. It's highly unlikely it's offered on a CPH-ARN flight--although the link is published on all booking pages as an option, it won't always complete--message appears saying your flight is not eligible. This would still only allow access to the SAS Business lounge. You can currently purchase SAS Business lounge (downstairs) access for 189 dkk (about 40.00 Cdn) -- there's a link on their website

(Also chances are pretty high your gate will be about a ten minute walk from the lounge)