The Constitution Act, 1867 states that the approval of the Crown, signified by Royal Assent, is required for any bill to become law after passage by both the Senate and the House of Commons.
(Source: Compendium of House of Commons Procedure)
All Chamber activity ceases with dissolution, and all incomplete business is terminated, including government bills and Private Members' Business.
The process is set in motion when the Prime Minister requests the Governor General, who represents the Queen as the head of state, to dissolve Parliament and to request the issue of writs by the Chief Electoral Officer for an election.
(Source: Library of Parliament - Parliamentary Information and Research service)
A Parliament may be dissolved at any time. If the House is sitting and there is not to be a prorogation ceremony in the Senate Chamber, the dissolution is usually announced to the House by the Prime Minister or another Minister. The Speaker then leaves the Chair without further ado.
(Source: House of Commons Procedure and Practice (Marleau and Montpetit) (2000 Edition))
Constitutionally, elections must be held every five years, although, by tradition, they are usually held at approximately four-year intervals.
"The party that wins the largest number of seats in a general election ordinarily forms the Government. Its leader is asked by the Governor General to become Prime Minister. If the government in office before an election comes out of the election without a clear majority, it has the right to meet the new House of Commons and see whether it can get enough support from the minor parties to give it a majority. This happened in 1925-26, 1962 and 1972."
(Source: How Canadians Govern Themselves)