He had an excellent half a season 2015/2016, instead of making a supper star out of him; they went on and bought Xhaka (a good player; but not that much better than Elneny), for no reason they decided to side line Elneny.
Elneny came into the side last season as Arsenal slumped towards the finish line, initially partnering Coquelin, but then playing alongside Aaron Ramsey as Coquelin was taken out of the starting eleven.