I have tried that out a bit; Nacho's code is in a very old version (2.4 was the current version in 2005), so converting with convert-ly did not work really well. I tried a bit of cut&paste and got a more or less working file, but the text was definitely not under the syllables where it should have been. I thought that might have been due to a typo, but that was apparently not the case; presumably the format for lyrics changed in the last 12 years? In case it is of use to anyone, I attach the Lilypond-file and the PDF.

Here is a revised version of Protasius' modified Lilypond file and PDF from it.

First I removed the explicit bar lines and relied on Lilypond's automatic bar function. It's easier to work with the .ly files and also to troubleshoot.

Next, I removed the explicit spacing in the lyrics, which were there for the melismas. Again I relied on Lilypond's automatic function using slurs. Ditto the reasons above

Third, I used Lilypond's relative pitch function in order to eliminate most of the ocaviation marks. Ditto reasons above.

All these things can work the way the original file was written, but it's very difficult to wade through the .ly file and to troubleshoot - counting everything to make it come out even, finding a mistake, which may not always be where you'd think it is, etc. I prefer to let Lilypond do a lot of the tedious work.

Finally, I spruced it up with some spacing and, line breaks, extenders on some melismas, etc.

All these things make a more "modern" looking score, which may not be what you want. But, in my opinion, it is also easier to read.

Hope the helps.