arrangement - copyright belongs to the arranger. Copyright will exist in new arrangements even if the music itself is out of copyright
Lyrics - copyright belongs to lyricist
Published edition - Copyright belongs to publishers
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Copyright in unpublished scores and lyrics lasts indefinitely. Once the work is published, copyright lasts for 70 years from the year the creator died or if not published during the creator’s life, 70 years from the end of the year of publication.
Copyright has expired in the works if the creator died before 1 January 1955, but remember that a current arrangement of an old score will still have copyright protection.