尊敬語 => Honorifics N4
に先立って => before; prior to ~ N2
に[先立「さきだ」]って/に[先立「さきだ」]ち/に[先立「さきだ」]つ => Before A occurs/takes place N2
Time, Situation
[尊敬語「そんけいご」] => Respectful form of A N4
Honorifics