Beloved Brother/Sister, there is no such thing as a 'muslim' name; for one is recognized as a believer in the sight of Allah SWT because of his belief and deeds, not because of his name. The meaning of this name is "ruler" and it's origin is Indian.
And If one wishes to name their child 'Arhaan', it would be a perfectly acceptable name in Islam. If the question was 'is it a good name?', then we would advice that there are plenty of better names one may keep for their children.