Fr. Lombardi indicated during the press briefing today (going on as I write), that the date of the beginning of the Conclave may be announced this evening, at 7 p.m. Rome time.
It would probably – not for sure – be early next week.
The Cardinals meeting in General Congregation (now that all the Electors are present and sworn in) will vote on the matter in the afternoon/evening meeting.
According to the Motu Proprio of Benedict XVI just before his retirement, said that the Cardinals could move the date forward. Cf. Universi dominici gregis 38 (modified).
Also, according the UDG 38, the College voted to accept the motives for the absence of the Cardinals who are not coming (the Cardinal from Indonesia for health reasons and O’Brien for “personal” reasons).
There are now, officially, 115 Electors. 77 are going to required to elect a new Pope.
The site adoptacardinal.org was mentioned in the press briefing.