He's turned into Scrooge. Working late at Highbury Counting House, personally overseeing every penny the club spends. I bet he doesn't even give Boro and Mickey a day off at Christmas.
The staff dread the final working day of the month. Arsene tells everyone that nobody goes home until every single penny has been accounted for. Sitting at his desk with piles of receipts becoming irate when he sees that petty cash is down £1.12.