align on char

[John Hunter]

Suppose you have a sequence of strings, all known to have at least one
occurance of char

lines = (
'user1 : John Hunter',
'another user : Bill Bragg',
'yet on more : Hi There',
)

what is the best / easiest / most elegant way of producing this?

aligned = (
'user1 : John Hunter',
'another user : Bill Bragg',
'yet on more : Hi There',
)

Thanks!
JDH