Emil de Cou conducts the National Symphony Orchestra in a Wolf Trap performance with folk legend Arlo Guthrie along with the eclectic ensemble Time for Three. Violinists Zachary De Pue and Nicolas Kendall and bassist Ranaan Meyer merge classical, country, gypsy and jazz. Good mornin', America, how are ya? Saturday, Aug. 6, at 8:15 p.m. Wolf Trap, 1645 Trap Road, Vienna. Tickets are $20 to $52. Call 703-255-1900 or visit wolftrap.org.