Hobhouse wrote in his diary for May 31:

Called [on] Madame Letort – found her and her husband painting military maps, so I presume war is about to begin. General Letort talks of the French separating Wellington and Blucher.

Conchran, Peter, Hobhouse’s Diary, 17 HundredDays, page 221

A key element of the conventional history the campaign in Belgium in 1815 in that Napoleon intended to separate the Allied armies and defeat them in detail.  This was possibly an ideal outcome or hope that Napoleon entertained, but there is little that supports this theory.  Certainly none of Napoleon’s contemporary orders suggest this was the goal.  On the contrary, all the contemporary correspondence as well as Napoleon’s memoirs suggest that Napoleon intended a rapid occupation of Brussels.  Napoleon expected that by coming between the Allied armies they would be compelled to fall back as neither army could make a stand against Napoleon in isolation.

The fallacy with the idea that Napoleon planned on defeating each Allied army is that it supposes Napoleon could rely on each giving battle, including a second major battle after the first had been defeated!  History, and especially military history, is often dominated by hindsight analysis.  That this campaign had any major battles at all was a surprise to Napoleon as will be clearly demonstrated.

While Napoleon’s memoirs cannot be taken as absolute, and they have significant editorializing and interpretations that paint Napoleon in the best possible light, we can easily compare much of what Napoleon in exile to what he said during the campaign.  Our analysis will have far more detail than Napoleon had when he recounted these events, and as such, we’ll see where Napoleon was wrong both in exile and in Belgium – these were not purposeful mistakes, but ignorance that played a key role in Napoleon’s defeat.

It is absolutely clear that Napoleon’s plans required separating the Allied armies.  This was obvious to  all participants, and thus it is not a surprise to see Hobhouse hearing this fact from Letort.