Ask-a-Dave's-Gardener: Pruning Lilacs, 2 by Cheddarsmama

Cheddarsmama wrote:
I live in Tucson, AZ and have taken over care of my mom's potted Lilac. I recently took out all the suckers and deadwood, but don't know what to do from here. I know it needs to only have 3 or 4 trunks, but I don't know how to pick which ones to keep and which to chop. I also don't know how to prune the ones that will be left. I want to see it bloom next Spring. It has bloomed once upon a time, so it's not impossible Any experts out there who can tell me what to hack just from a photo??