Brothers & Sisters will have one episode this coming March 22nd with episode 3.20 “Missing”. Then there is a 3 week hiatus. B&S will return on April 19th starting with episode 3.21 and end on May 10th with the last episode of the season with 3.24.

Schedule:

March 22 : Episode 3.20 “Missing” (Luke is a definite in this episode)
April 19 : Episode 3.21 “S3X” (Luke is a definite in this episode)
April 26 : Episode 3.22 “Julia” (Luke is a definite in this episode (confirmed by Luke himself))
May 3 : Episode 3.23 “Let’s Call the Whole Thing Off” (Luke says he is in it, but he is unsure)
May 10 : Episode 3.24 “Mexico” (Season Finale) (Luke is a definite in this episode)

No word from ABC about renewal for Season 4.