The -p flag treats the file one line at a time so your first regex will never match. Overcome this with -0:

$ cat in
foo
bar
Ubar
Ubaz
quux
$ perl -p0e 's/\nU/U/g' in
foo
barUbarUbaz
quux
$

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In reply to Re: Remove SOME new lines by hippo
in thread Remove SOME new lines by RenMcCourtey

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