\version "2.11.39"

\header { title = \markup {\column {"Clef for cue notes " "should only be shown" "after line break!"} } }
\paper { line-width = 4\cm }

% just change the clef (shown in smaller font)
setClef = #(define-music-function (parser location clef) (string?)
   #{ \once \override Staff.Clef #'font-size = #-3 \clef $clef #} )

Solo = \relative c'' {
   \clef "bass"
   c,,2 c | \break
   \cueDuring #"vIQuote" #UP { \setClef "treble" R1*2 \setClef "bass" }\break
   c2 c |
}

vI = \relative c'' { \clef "treble" f2 f | f f | f f | f f |  }
\addQuote vIQuote { \vI }

% Solo score with cue notes, unfortunately the clef change of the cue notes 
% shows the clef at the very beginning of the line!!!!
\score {
  \new Staff \Solo
}