Yes. However, as I mentioned a few minutes ago, CSE is a technology agency that operates abroad. Other security agencies, such as the police, may occasionally ask for CSE's help. That's also part of CSE's mandate. CSIS, in particular, can ask for CSE's help if it's spying on someone abroad but doesn't have the necessary technology. CSE will agree to help, but only if the agency is legally authorized to act. If that's the case, CSE will assist CSIS.
On March 21st, 2017. See this statement in context.