No. Non-confidence can be called on B C D etc or the GG can take the reigns until we hit the polls again.
If there is a Conservative minority government and there is a vote of no-confidence in Harper, the Governor General has two options:
1.) Go to another election
2.) The other parties get to decide who would form government and become PM
If option#2 applies and they can't decide then we go to another election.
The GG will not pick option#1 unless Harper was just shy of a majority and he thinks another election would guarantee a majority.
In option#2 there is no way the other parties will disagree unless their respective seat count is very close and there is a strong chance one of them could emerge with a majority in another election.
The likeliest scenario is that they oust Harper and agree that Shiny Pony would lead and form government.