Arduous time following drunkard's last dry spell (7)
I believe the answer is:
drought
'dry spell' is the definition.
(I've seen this before)
'arduous time following drunkard's last' is the wordplay.
'arduous' becomes 'rough'.
'time' becomes 't' (abbreviation).
'following' means one lot of letters go next to another.
'last' suggests the final letters.
The last letter of 'drunkard' is 'd'.
'rough'+'t'='rought'
'rought' after 'd' is 'DROUGHT'.
(Other definitions for drought that I've seen before include "Prolonged shortage of rainfall" , "Lack of rain" , "Prolonged dry period" , "Hot drug (anag)" , "Period of low rainfall" .)