I would like to add
http://j-lyric.net/
to the whitelist of lyric relationship URLs. The site has a more comprehensive database than Kasi-Time (going farther back with regard to release dates). As for licensing, the "About" page
http://j-lyric.net/info/e373.html
explicitly states that the site is licensed by JASRAC (Japanese Society for Rights of Authors, Composers and Publishers).
Just to note: A link to an artist will look like

http://j-lyric.net/artist/a054174/
while a link to an individual lyrics page looks like
http://j-lyric.net/artist/a054174/l021a2d.html