Lassie in heaven? (3,4)
I believe the answer is:
dog star
'lassie in heaven?' is the definition.
'dog star' can be an answer for 'lassie' (I've seen this before). I am not sure about the 'in heaven?' bit.
'lassie in heaven?' is the wordplay.
'lassie' becomes 'dog' (I've seen this before).
'in heaven?' becomes 'star' (I can't explain this - if you can you should give a lot more credence to this answer).
'dog'+'star'='DOG-STAR'
Can you help me to learn more?
(Other definitions for dog star that I've seen before include "slightly flashy night-spot?" , "clearly visible shiner" , "Lassie, perhaps" , "Sirius in the sky" , "heavenly body?" .)