Just wait. Colder soil slows a plant down, and it was an odd winter most everywhere in the US. If the canes look okay, then once the soil warms up more, everything will be fine. :^)

Listen to hoov and be patient. It's been a really nasty winter for us and the roses. The soil is taking much longer to warm than usual and the roots can't support new top growth until they can easily absorb and send water and nutrients up to keep it going. The larger the plant the more energy that takes and I'm betting your Cecile is a good size after six year. Make sure you prune off any dead cane or tip die back and then wait for the weather to catch things up.

I have a 15 year old specimen of Mlle. Cecile, large enough to hide a small house under. This year, 90% of the canes are dead, thanks to the Polar Vortex. What few canes survived, I will leave till after (IF) they flower and then cut the whole mess down and make it start over. I expect you will find you have to do the same. If it hasn't leafed out by now, its not likely going to. This rose doesn't tolerate temps as low as what we got this year.