There's been a gentleman here asking for you, sir.
As far as I know, In this form the participle always comes immediately after the object of the main clause.
After I saw this sentence above. A question came to my mind: Can I use an adverbial phrase between the object of the main clause and the participle clause? I think the question I quoted above does that.
1- I found him under the tree waiting for me.
2- I left my cat on my bed lying down.
3- Stream pushed the ducks along the riverside whistling to each other. (In the meantime, the ducks were whistling to each other.)