Adding braces to centered/dropped lyrics

[Tom Dickson]

Hello,

I'm trying to combine the two snippets found here:

http://lsr.dsi.unimi.it/LSR/Snippet?id=503
http://lsr.dsi.unimi.it/LSR/Snippet?id=265

But adding the \rightbrace is adding a bunch of space above the first verse, 
and also it is not correctly centered on the verse - the center of the brace 
should align with the center of the capital A that follows, be directly between 
the two lines, and should be much closer to the preceding parts.

The whole file is available here: http://schnecke.bombcar.com/random/braces.ly

If I change the line:

alleluia = \lyricmode { \dropLyrics \markup {\rightbrace Al} -- le -- lu -- ia! 
\raiseLyrics }

to

alleluia = \lyricmode { \dropLyrics Al -- le -- lu -- ia! \raiseLyrics }

Then the lyrics are placed correctly, but of course I don't have the braces 
appear.

Is there a way to make it center correctly?