That depends. Technically you can only claim business expenses once your business has begun, but exactly when a business starts is not always clearcut. The Canada Revenue Agency decides each individual case on its own merits, although they state in their Business and Professional Income Guide that they generally consider that a business starts "whenever you start some significant activity that is a regular part of the business, or that is necessary to get the business going".
So whether or not you can claim these particular business expenses will depend on whether or not they are deemed "significant" or "necessary" to the actual operation of your business.
If in doubt as to whether or not you can claim business expenses, I recommend that you ask the CRA about your particular circumstances and/or ask your tax accountant.
