Is it forbidden to pray while having the trousers folded above the ankles and the sleeves above the elbows during ablution?

The most preferable for the worshiper is to be in his natural state during prayer. If he rolled up his sleeve for an action like ablution, there is no harm in entering prayer in that state, although it is better to adjust it. However, if he did that for the sake of prayer, it is not appropriate, as it has been forbidden if it is intended for prayer. Thus, there is no dislike in your action as long as you did not do it for the sake of prayer.