Yes an unlocked blackberry mobile work with Telus network but make sure that the mobile is unlocked properly .Check that it unlocked or not by the following way ,
Switch on your mobile phone with a sim card from a network other than the network you are currently with. If you are able to use the phone, you can be sure that your phone is not locked. If your phone displays an error message saying "Wrong sim" or "Incorrect sim" or "Emergency calls only", etc., then your phone is probably locked.Get the unlocking service from a good service provider like UnBBlock.com .