\pointAndClickOff

incipitA =
#(define-music-function (parser location incipit-music) (ly:music?)
  #{
    \once \override Staff.InstrumentName.self-alignment-Y = ##f
    \once \override Staff.InstrumentName.self-alignment-X = #RIGHT
    \once \override Staff.InstrumentName.stencil =
      #(lambda (grob)
        (let* ((instrument-name (ly:grob-property grob 'long-text)))
        (set! (ly:grob-property grob 'long-text)
          #{ \markup {
            \score
            {
              \new Staff
              {
                \once \override Staff.InstrumentName.self-alignment-X = #LEFT
                \set Staff.instrumentName = #instrument-name
                $incipit-music
              }
              \layout { $(ly:grob-layout grob)
                line-width = 8\cm
                indent = 2\cm
                ragged-right = ##f
                ragged-last = ##f
                \context {
                  \Score
                  \remove "Default_bar_line_engraver"
                }
              }
            }
            }
          #})
          (system-start-text::print grob)))
  #}
)

incipitB =
#(define-music-function (parser location incipit-music) (ly:music?)
  #{
    \once \override Staff.InstrumentName.self-alignment-Y = ##f
    \once \override Staff.InstrumentName.self-alignment-X = #RIGHT
    \once \override Staff.InstrumentName.stencil =
      #(lambda (grob)
        (let* ((instrument-name (ly:grob-property grob 'long-text)))
        (set! (ly:grob-property grob 'long-text)
          #{ \markup {
            \score
            {
              \new Staff
              {
                \once \override Staff.InstrumentName.self-alignment-X = #LEFT
                \set Staff.instrumentName = #instrument-name
                $incipit-music
              }
              \layout {
                line-width = 8\cm
                indent = 2\cm
                ragged-right = ##f
                ragged-last = ##f
                \context {
                  \Score
                  \remove "Default_bar_line_engraver"
                }
              }
            }
            }
          #})
          (system-start-text::print grob)))
  #}
)

\score {
  {
    \set Staff.instrumentName = #"Altus"
    \incipitA { f''1 }
    \repeat unfold 10 c''1 \break
    \repeat unfold 10 c''1
  }
  \layout { indent = 8\cm }
}

\score {
  {
    \set Staff.instrumentName = #"Altus"
    \incipitB { f''1 }
    \repeat unfold 10 c''1 \break
    \repeat unfold 10 c''1
  }
  \layout { indent = 8\cm }
}