You can sow them now and see what happens, and save some for sowing in the spring. They may not come true to their original colour though, thats what makes it interesting :))

I sow mine now into little pots and overwinter the young seedlings in a sheltered spot and plant them out in spring when they've put on a bit of growth. Pots because:

1 - I know where they are so won't weed them out by mistake
2 - slugs love young lupins- although they will still need protecting