Lalaing's English wikipedia entry is here, and his French entry is here.
However, the best source of information on him is this fine web site containing biographical information and many examples of his work.
Painted when Lalaing was about age 25. I don't find it very impressive.
Lalaing made a number of highly detailed pastel portraits that, viewed digitally, are hard to distinguish from oil paintings. This was made the same year as the oil painting below, so it's possible that it is a study. On the other hand, the third link above has an example of a pastel that looks like the study of a head in an oil painting, but is dated a year later than the painting (the subject is Ghislaine de Caraman).
Sister-in-law of the artist. It seems that this was damaged by a German shell (obus, in the web page text). More likely it was done by a shell fragment, probably in 1914 when the German army overran most of Belgium.
This photo was probably used by Lalaing as reference for the clothing and the pose. Christine's face differs in liveliness and attractiveness -- photographic portraits were often stiff affairs in the 19th century.
A later portrait, very nicely done.
Lalaing also portrayed men.
A work made shortly before the war and ill health curtailed Lalaing's career.