Members' area
A very good alternative to playing mp3 files in your browser or in the Windows Media Player is the program VLC Media Player, which is downloadable free of charge from the website:
Here are some suggestions for practice tracks:
Choralia https://www.choralia.net/mn02mp3/mn02mp3en.htm with electronic voice parts;
Cyberbass
https://cyberbass.org/Major_Works/Mendelssohn_F/Mendelssohn__Elijah.htm
which provides individual, instrumental voice lines without accompaniment.
Chordperfect
A further option for practising at home can be found at https://www.chordperfect.com/felix-mendelssohn/. This version has real, human voices, which many of us will find more acceptable.
We are not able to link the John Fletcher site on our website, but recordings for Elijah are also available on the his website and are accessible for this work without needing membership.