Keep in mind wet weather holding Lawrence back (6)
I believe the answer is:
retain
'keep in mind' is the definition.
'wet weather holding lawrence back' is the wordplay.
'wet weather' becomes 'rain' (I've seen this before).
'holding' is an insertion indicator.
'lawrence' becomes 'te' (TE Lawrence, Lawrence of Arabia).
'back' says the letters should be written backwards.
'te' in reverse letter order is 'et'.
'rain' enclosing 'et' is 'RETAIN'.
(Other definitions for retain that I've seen before include "Not relinquish" , "Hold in position" , "Keep in place" , "Hold on to or employ counsel" , "Keep; remember" .)