Seed pods that produce good seed will keep the seed until late fall and even into the winter. (I have collected seed in January!)
Pods will open up slightly in fall. Apparently one can pick a stalk and the seed pods will continue to ripen in a dry environment.

thanks for your reply sharont, It's good to know. I know now what to expect. I was surprise to hear you were able to collect them in winter, great.

I was once successful in harvesting and growing the seeds of Frances Williams hosta. None of the offspring had the lime coloured edge but the plant looks pretty much like a regular Sieboldiana Elegans.