How to make vertical arrow between staves

[Rutger Hofman]

Good morning list,

in Berg's Violin Concerto, bar 93, there is a vertical arrow between the 
solo violin and the first violins. See attached. I am convinced this is 
a voice follower indication. This construct occurs numerous times in 
this score, as in many other works by Berg.

I don't know how I can make this in Lilypond. An obvious construction 
(which appeals to me because it is 'semantically correct') would be a 
separate invisible voice and a 0-length starter note like:

   ... g4*0 \once \showStaffSwitch \change Staff = mvtIvlnI g8 ...

and the arrow can be obtained by \override 
VoiceFollower.bound-details.right.arrow = ##t (found on the web, 
although I couldn't locate the specs for bound-details.right in the docs).
But this doesn't work. It gives me some warnings about 'adding note head 
to incompatible stem' and doesn't display the voice follower.

Making some time distance between start and end note of the voice 
follower of course works, but then the arrow is not vertical, which is 
obviously Berg's intent.

I also tried cross-staff glissando, but again to no avail.

Is there any other way to achieve this voice follower? Can I force the 
angle of the follower line? Or should I try to abuse glissando, for 
instance?

Obviously, an arrow can be drawn in markup, but that is not really 
portable. Its length would be fixed, and need to be retuned for each 
different situation, or score/parts, or whatever. I would love to stay 
away from that.

Rutger Hofman
Amsterdam

berg-conc-vln-16.png
Description: PNG image