Capital of Laos: Louangphabang? (4)

I believe the answer is:

oslo

'capital' is the definition.
(capital of Norway)

'of laos louangphabang?' is the wordplay.
'of' indicates a hidden word.
'OSLO' is hidden within 'laos louangphabang'.

(Other definitions for oslo that I've seen before include "Northern city" , "Location" , "foreign port" , "City in Norway" , "European capital, known until 1924 as Christiania" .)

I've seen this clue in The Everyman puzzle in The Observer.

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