The most common and most likely answer to this crossword clue is the 1 plus 5 plus 2 plus 1 plus 3 letter word A BROTH OF A BOY
I've seen this crossword clue in The Guardian
A
B
R
O
T
H
O
F
A
B
O
Y
More clues leading to the result A BROTH OF A BOY
Buddy explains!

The straight part
We know that "Lovely lad" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lovely lad = a broth of a boy.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.