As I understand it, in Britain by law, the monarch only may prorogue or dissolve Parliament on advice of the Privy Council, and further that the legal effect of such an act by the Crown is dependent not only on the advice of the Council but on the legality of that advice, which can be struck down as unlawful by the courts negating the effect of the order; it is a power of the Queen (or King)-in-Council as the power to create law is of the Queen/King-in-Parliament.

I would be surprised if the monarch retained greater independent personal authority as Queen of Canada.