Sensational 20 Year Old Pianist Lang Lang Performs Beethoven's Piano Concerto No. 4 with The Saint Louis Symphony Orchestra WHO:  The Saint Louis Symphony Orchestra James Judd, conductor         Lang Lang, piano WHAT:   BEETHOVEN  Piano Concerto No. 4         ELGAR  Symphony No. 1 WHEN:  Friday, January 31, at 8:00 p.m.          Pre-concert lecture at 7:00 p.m.        Saturday, February 1, at 8:00 p.m.         Pre-concert lecture at 7:00 p.m. WHERE:  Powell Symphony Hall, 718 N. Grand Blvd. (at Delmar) in Grand Center TICKETS: $10 - $91.  Available at the Powell Symphony Hall box office, by telephone at (314) 534-1700 and online at www.slso.org.  Ask about our special student and senior citizen discount rates.  Group rates are available to groups of 20 or more by calling (314) 286-4126.  Twenty-year-old pianist Lang Lang burst upon the international musical scene with unparalleled excitement and acclaim, when he filled in for an indisposed Andre Watts at the Ravinia Festival in 1999.  Returning to Powell Symphony Hall at 8:00 p.m. Friday, January 31, and Saturday, February 1, he will perform Beethoven's introspective Piano Concerto No. 4 with the Saint Louis Symphony Orchestra.  Also featured in the concerts, conducted by James Judd, music director of the New Zealand Symphony Orchestra, is Elgar's grand Symphony No. 1.  Mr. Judd, a frequent and much-admired international guest conductor, is making his St. Louis debut. Concert ticket holders are invited to attend an informative pre-concert perspective presented by Washington University Music Professor Hugh Macdonald one hour prior to the start of both concerts.