I will try to explain, but don't shoot me if there are some mistakes in the following explanation
Every player can commit to a tournament where he wants to play, but only the highest ranked players will get a chance to get into the main draw. Than there's a bunch of players who can still play qualifications to get into the main draw. The rest won't get a chance to play in this tournament, except if a qualifier withdraws before the tournament starts and a lower ranked player can replace him as being an alternate. An other way to get into such a tournament without having a high enough ranking is to get a wild card from the organisation of the tournament.
Now to get back to the case of Kristof:
He has already committed to some tournaments in the near future, when he was still having his good ranking. His result in Adelaide won't affect this ranking, it will stay the same as when he committed to these tournaments. So for a little while he can still play some bigger tournaments and will get easier into the main draw of an event. This will only be for 3 or 4 weeks I guess... When we are that far he will enter a commitment list with his new - lower - ranking. That means he can't play the bigger tournaments anymore, he'll probably has the play again challengers, where one can't win as much points as at ATP-tournaments.
Well, actually it is harder to explain than I thought it would be. Hope you'll understand.