It doesn't say IFR conditions. The subtle difference is that it wants to know the conditions under which you operated.
at night
or under Instrument Flight Rules
I understand what IMC is...Instrument Metorlogical Conditions (when you can't comply with the Visual flight Rules because your not in VMC). There is no such definition for IFR conditions. Just a definition for IFR.
Instrument flight (IF) it says is to be noted in the remarks column.
In the IEM pages at the back of JAR-FCL 1 there are examples of log book pages to comply with the regulations. No instrument flight time column just a remarks column for that.
But there is a specific IFR column. There emphasis appears to be on time conducted under Instrument Flight Rule (IFR).
I think 12watt tim explained it better.