I'm going to move this thread over to the US forum, where we'll find many more people capable of answering your question.
Since the HP clubs have been effectively merged into the US Airways Club system, the rules are now common for all clubs, in all locations, including the PHX clubs. And, since the Star Alliance Gold members are all over on the US side of the airlne (HP elite members don't have that status until the programs are combined), they'll have experience with whether Gold members can use US clubs when flying to Canada.
AZ
HP forum Moderator