Date unknown. Accepted puzzles are sorted by day of the week, then go into a bin with other puzzles of the same day. They've got a backlog of about six months, if I remember correctly (possibly even longer for Sundays), but beyond that, I find out when it goes in when it actually goes in. Luckily, I've got xwordinfo.com at my disposal, so I'll keep watch and let folks know when it turns up.