Come out straight, curl, then uncurl when they are going to bud/flower. I cut them when straight or starting to curl. I've read/heard to cut them when they make one curl. I never wait that long. I prefer them to be tender. I don't want the scape to get "woody". I usually just eat them on site as cutting. I'm told I have bad breath for the month of scapes.

https://www.youtube.com/watch?v=8ALlS-1SM8o

I pick my scapes when between 12" and 18" long regardless of whether they are still straight (rare) or in curl (usual). They are very tender at this stage.

If you leave the scapes on until they stand straight and flower the bulbs will be somewhat smaller. Best to pick all of the scapes when tender and enjoy them. The bulbs are ready to dig when about half of the leaves are yellow/brown. I take mine when the top four leaves are mostly green.

TomNJ/VA