We looked online at a bunch of policies and it looks like most do include trip cancellation coverage as part of 'all-inclusive' travel insurance policy. But to be sure, when buying your policy make sure that it explicitly includes everything you want to be covered for, including trip cancellation. Don't just assume it does.
In addition to making sure the policy you buy has trip cancellation, make sure you know under what situations you will be covered by reading the policy. I know it doesn't sound appealing, but it is the only way to know under what circumstances a cancellation will, or will not be covered by the policy you bought.
For example, will you be reimbursed if you cancel your trip because the government of Canada issues a travel advisory against it (like the H1N1 flu and the Mexico travel advisory?) These are important things to know when you buy your policy, and these are the types of details that you will find in your policy.
For more information about travel insurance, you might want to check out the following industry-related websites:
Canadian Life and Health Insurance Association -
www.clhia.ca - they have a 'Consumer assistance' section that includes a brochure about travel health insurance
Financial Services Commission of Ontario -
www.fsco.gov.on.ca - they have a section about travel medical insurance and a downloadable brochure that you might find helpful.