THE internationally acclaimed Pacific Chorale gives a performance of great choral music at the Hongkong Cultural Centre on July 11 (Sunday) at 8 pm. Under the baton of John Alexander, with the accompaniment by the Hongkong Sinfonietta, the chorale will perform Felix Mendelessohn's monumental oratorio Elijah . Praised as one of the finest choral groups in the United States, the group is also respected for its difficult and ambitious repertory of great choral masterworks and has consistently received popular acclaim under the skilful guidance of its artistic director. The California Arts Council described the Pacific Chorale as ''artistically exemplary, with a broad, interesting repertoire and the stylistic versatility to match''. Artistic director Mr Alexander is famous for his effective interpretations of musical scores, having conducted more than 100 choral and orchestral works. He has also made extensive guest appearances with world famous orchestras. Mr Alexander is also professor of music and chairman of choral activities at California State University, Northridge. Tickets at $120, $100, $80 and $60 (half-price for students and senior citizens) are available at URBTIX outlets. Group booking discounts are also available. For telephone reservations call 734-9009.