This blogosphere lark is a tiny, tiny world. In doubt as to when exactly the word lorsque qualifies for an elision (lorsqu’Arnold or lorsque Arnold?), (hey, be indulgent, it’s Monday!) I found this extremely useful page on elision, which reminded me that lorsque

becomes lorsqu’ only when followed by the words il, ils, elle, elles, on, en, un, une. Lorsqu’il fait froid, but lorsque arrive l’hiver, lorsque à ce jour.

Impressed with the conciseness and clarity of the grammatical lesson, I went to the site’s home page and was delighted to see that it belongs to the author of one of my favourite blogs. Thanks for your help today Dominique!