"Technically," yes indeed, though strictly speaking the power's vested in the Crown, not the person wearing it. The Governors-General who act in the name of the Crown in the Commonwealth have the same powers, technically, but in practical terms it doesn't amount to much except under very unusual circumstances, in which the Crown's role is to provide continuity and stability. It's happened only once in Canada's history, what's called the "King-Byng Affair," in which PM Mackenzie King asked the G-G, Lord Byng, to dissolve Parliament, Byng correctly (in the judgement of most experts these days) refused and called on the Leader of the Opposition, Arthur Meighen, to try to form a government instead.
Interestingly, we're now in a situation in which such a thing could possibly happen again, with a minority Conservative government and some natural allies arrayed against it that might be able to form a government, though it'd probably be short-lived, as Meighen's was.
