Single staff polyphony and one lyric voice

[Christophe Dang Ngoc Chan]

Hello,

In a song, there is a second voice singing the same lyrics for a  
short time, so I would like to keep only one staff.

The following example is OK :

% ********** this does not work
\new Staff \relative c' {<<
   {  s2. e'8 e~
      e4 e8 e~ e2
   }
   {  r2. g,8 a~
      a4^\markup \fret-diagram-terse #"o;o;2;2;o;o;"
      b8 a~ a2
   }
>>}

\addlyrics {
   be -- hind
   blue eyes
}
% **********

Now I try to dissociate the two voices, and the lyrics do not align  
any longer.

% ********** this does not work
\new Staff \relative c' {<<
   {  s2. e'8 e~
      e4 e8 e~ e2
   } \\
   {  r2. g,8 a~
      a4^\markup \fret-diagram-terse #"o;o;2;2;o;o;"
      b8 a~ a2
   }
>>}

\addlyrics {
   be -- hind
   blue eyes
}
% **********

Any hint ?

--
Christophe Dang Ngoc Chan
address@hidden