Lacor was born in Wilrijk in 1956. He studied electromechanics at the Vrije Universiteit Brussel and obtained his doctorate in 1986 with the thesis "A Computational Method for Steady, Three-Dimensional, Inviscid, Subsonic Flows". He started his career as a researcher at the IWONL, after which he also became a researcher at the National Fund for Scientific Research in 1980. Lacor worked there as a senior researcher until 1987. From 1988 to 1990, he worked as a senior scientific researcher at the Faculty of Technology of the Vrije Universiteit Brussel. Afterwards he became successively lecturer and senior lecturer at the VUB. Lacor has worked as a professor at the same university since 2001. He was also chairman of the Research Group Fluid Mechanics and Thermodynamics.