In Toronto/YYZ a Concierge staff member, at least pre-covid, was easy to find as their office is quite clearly marked. It is at the far end of Domestic/International check-in desks about 25 ft past the Super Elite check in counter. You can certainly pop your head in there and make your ask.
Have not flown enough since COVID to know what service is like now but back in the day I would have said Toronto is too big and too many concierge for even SE to always get attention you are likely looking for. I always felt that Air Canada advertising International Signature getting concierge is a bit misleading as it is very clear its a two tier level of service and that non-SE pax do not get anywhere the same level of attention and service.
At smaller stations where this is 1-2 Concierge for the whole place it is a much different situation since that concierge is normally hopping between the check-in, lounge and gates. In Toronto they just put messages on your reservation which doesn't always work out.