Artist and old boys, having arrived with dog outside a room with a view (6,7)
I believe the answer is:
camera obscura
'a room with a view' is the definition.
(room containing a device for projecting a view)
'artist and old boys having arrived with dog outside' is the wordplay.
I cannot quite see how this works, but
'artist' could be 'ra' (Royal Academician, member of Royal Academy of Arts) and 'ra' is present in the answer.
'old' could be 'o' (common abbreviation eg in OE for Old English) and 'o' is found within the answer.
'arrived' could be 'came' (come can mean to appear or arrive) and 'came' is located in the answer.
'dog' could be 'cur' (both can mean a despicable person) and 'cur' is found in the answer.
The remaining letters 'bsa' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for camera obscura that I've seen before include "Small building with optical function" , "Box with lens for projecting image of external view" , "Imaging device" , "Dark room arranged to project outside objects" , "Early image-projection device" .)