Painter brings in a lost model (5)
I believe the answer is:
ernst
'painter' is the definition.
(Max Ernst)
'in a lost model' is the wordplay.
I cannot quite understand how this works, but
'model' could be 't' (Ford Model T car) and 't' is found within the answer.
The remaining letters 'erns' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'brings' is the link.
Can you help me to learn more?
(Other definitions for ernst that I've seen before include "Surrealist; stern (anag.)" , "He painted" , "Max --, German painter" , "Max -, twentieth century German Surrealist artist" , "Young partner" .)