Should database be denormalized if I need an index across multiple tables

I have a catalog of album & song names. The song has a foreign key to the album table. I expect queries like:

SELECT * FROM song s
JOIN album a ON a.id = s.album_id
WHERE LOWER(CONCAT_WS(' ', album.name, song.name) = 'Meteora Breaking The Habit'

I wish to create an index on the above type of search terms but it looks like I can't have an index across multiple tables. In this case, would it make sense to de-normalize the table and put the song & album name in a single table or is there a better approach?

Reference Table:

CREATE TABLE album (
   id SERIAL PRIMARY KEY,
   name text NOT NULL
);

CREATE TABLE song (
   id SERIAL PRIMARY KEY,
   name text NOT NULL,
   alubm_id integer NOT NULL,
   CONSTRAINT album_id_fk FOREIGN KEY (album_id) REFERENCES album (id)
);

P.S. For the sake of understanding, I'm ignoring the fact that query can be song name first & album name later. Also ignoring that query can contain band name too.