Your columbines look a little different from mine. Perhaps more than one variety exists, and I didn't know it. Mine are blooming now, too.

Shortly after I read your post, I ran across this in a gardening newsletter I receive: "Early Spring Flowering Trees and Shrubs (Crabapples, Lilacs, Forsythia, etc.) should be pruned for shape and size when the flowers have fallen. If done later, or when they’re dormant, you will cut off the next season’s flower buds."

So maybe a fall pruning of the lilacs isn't a good idea.