Originally from Arbitration Law of Canada: Practice and Procedure, 3rd Ed.

CHAPTER 4

COMMENCING THE ARBITRAL PROCESS AND CHOOSING AN ARBITRATOR 

4.1    RULES REGARDING COMMENCEMENT
Prior to commencing an arbitration, consideration must be given to what arbitral rules apply to it. If the arbitration is to take place in Canada, then absent an agreement between the parties, the applicable domestic or international Act will apply. It is important to determine before commencement of the arbitration whether it is governed by a province’s domestic Act or its international Act, which incorporates the Model Law. The law of the contract does not determine the procedural rules or procedural law of the arbitration. The procedural law is the law at the place or seat of the arbitration. If the parties have agreed to procedural rules or have chosen an institution to administer the arbitration then those rules will apply, subject to any mandatory arbitration law at the place of arbitration. 
One must follow whatever rules are applicable for the proper commencement of the arbitration. In the case Bell Canada v. The Plan Group,  the arbitration agreement provided that the notice of arbitration was to be filed in accordance with the rules of the Arbitration and Mediation Institute of Ontario Inc. A further clause provided that failure to file a notice of arbitration within 12 months after the occurrences complained of would constitute an irrevocable waiver of that claim.  The claimant served its notice of arbitration on the respondent but failed to file a copy with the Institute in a timely manner.  The Ontario Court Appeal held that the arbitration had not been commenced within 12 months as the requirement of filing the notice with the Institute under its rules had not been complied with. 
Under the Domestic Acts, there is no specified way to commence an arbitration. For example, section 23 of the Ontario domestic Act provides:
(1)    An arbitration may be commenced in any way recognized by law, including the following:
(a)    A party to an arbitration agreement serves on the other parties notice to appoint or to participate in the appointment of an arbitrator under the agreement;
(b)    If the arbitration agreement gives a person who is not a party power to appoint an arbitrator, one party serves notice to exercise that power on the person and serves a copy of the notice on the other parties;
(c)    A party serves on the other parties a notice demanding arbitration under the agreement.
The Quebec Code of Civil Procedure provides that arbitration proceedings commence on the date of the notice sent by one party to the other, which specifies its submission of a dispute to arbitration and the subject matter of the dispute.  
If you commence litigation and later determine that you should have commenced arbitration, you cannot allege that the Statement of Claim is sufficient to have started the arbitration.   
Under the Model Law, Article 21 provides that unless the parties agree otherwise, the arbitral proceedings commence on the date on which a request for the dispute to be referred to arbitration is received by the respondent.