The 32-year-old is now playing regularly for Liverpool and Wenger is delighted to still see him in the Premier League.
"I am pleased for him because he came here completely unknown and made a great career," he told Arsenal Player.
"He's a boy that's dedicated, has sympathy for everybody, speaks with everybody and loves football passionately so you are happy that he is happy.
"Yes [he is one of my most satisfying signings] because he failed tests nearly everywhere; at two French clubs, at a Swiss club and nobody kept him.
"I kept him here after the tests, so he was not good enough for the smaller clubs but he made it in a big club. Maybe that was his luck as well.
"One of the things that convinced me was his sheer enthusiasm for the game and his huge desire to do well. As you know a successful life is about attitude and he had the right attitude and got the opportunity with us."
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