Arthur had a short spell with the Cobblers under Gary Johnson but was allowed to leave Sixfields after Aidy Boothroyd's arrival.
“I feel I have something to prove," he said, quoted on the Get West London website.
"He let me go for a reason and it’s up to me to show what I can do."
Get West London
After playing for Havant & Waterlooville, Arthur joined AFC Wimbledon in the summer and has been used mainly as a substitute by manager Neal Ardley so far this season.
Source: Cobblers Mad