Harper has prorogued parliament before..

If Harper prorogues parliament it will not be the first time he has used this as part of his bag of tricks and schemes. He prorogued parliament in 2007:


Harper prorogues Parliament, sets new session
Could set the stage for confidence vote and election
Last Updated: Tuesday, September 4, 2007 5:48 PM ET
CBC News
Prime Minister Stephen Harper said Tuesday he will ask Gov. Gen. Michaëlle Jean to prorogue Parliament, short-circuiting the current session, which was set to resume Sept. 17.
MPs will be recalled Oct. 16 to start a second session of the 39th Parliament with a speech from the throne, he said in a statement.

There is no mention of any need for the opposition parties to consent to the action. I do not know where people get the idea that it would require the consent of the opposition. Here is what the official government site has to say about proroguing parliament:

Parliamentary Cycle
Prorogation of Parliament
The prorogation of Parliament ends a session. This is done by the Governor General, on the advice of the Prime Minister, either by means of a special ceremony in the Senate Chamber, or by the issuing of a proclamation published in the Canada Gazette. Both the Senate and the House of Commons stand prorogued until the opening of the next session.
During a period of prorogation (or recess), the Speaker, the Prime Minister, Ministers and Parliamentary Secretaries remain in office and all Members of the House retain their full rights and privileges.
The principal effect of ending a session by prorogation is to end business. All government bills that have not received Royal Assent prior to prorogation cease to exist; committee activity also ceases. Thus, no committee can sit after a prorogation.
In order for government bills to be proceeded with in a new session, they must be reintroduced as new bills or they may be reinstated, if the House agrees to this.
The Standing Orders provide for the automatic reinstatement of all items of Private Members' Business in a new session. Committee work may also be revived either by motion in the House, or in committee, depending upon the nature of the study.
Prorogation does not affect Orders or Addresses of the House for the tabling government reports required to be tabled by statute. Requests for responses to committee reports or petitions are still valid following a prorogation. These continue in force from one session to another, but are ended by dissolution.