If you follow the normal recommended path after landing, the answer is no. You will go directly to the T1 International area, with no access to T1 domestic (or T3 International).
The only option I can think of is to go through normal Canadian immigration (i.e. not to go through the connecting International flight immigration queue), and then buy a refundable domestic ticket on Air Canada to get into into the domestic terminal at T1. (And then cancel it once you are in the lounge).