The Egypt midfielder spent last season on-loan with Besiktas.
Arteta said, "I know Mo really well.
"I played with him, so I know what he can be and I know his strengths and weaknesses really well.
"He's a really positive character to have around and he has some really good qualities as well and like anybody else, in the moment that he is with us, he will be given all our support and the best possible environment for them to perform as high as they can.
"We don't know [if he will stay]. The sixth of October is still too far, as I said. It's pretty unpredictable to know what's going to happen."