As people have said it is individual for each hotel. I have 3 examples to show:

1) CP Warwick, RI - nice upgrade to suite but no club lounge
2) CP Times Sq NYC - through email contact before stay manager confirmed for me Plats get upgraded to Concierge (club) floor room if available. If not still get Concierge Lounge access ^
3) CP Detroit airport - pretty much same policy as #2. They always give access to lounge and try and put you on that floor.