Weights for arms - ladies

Hi All,

I was just wondering if you could look at my profile picture at my arms. I used to lift heavy weights and have obviously built muscle, that's what I was meant to do.

But now I want the leaner look - Do I lift lighter weights but more reps?

Also I haven't lifted in such a long time, and I am surprised this definition is still there to be honest. Maybe its because I am still consuming enough protein? As surely the muscle mass would have decreased by now. Obviously I am still using my arms at the gym - But I have been in the cardio section at the gym a lot, and not the weights.

I suppose its a good thing I haven't lost muscle, as I have read a few articles saying losing muscle is not good, and the more muscle mass you have, the more calories you burn - Is this right?

Thanks!