Some extra hints about the differences between one word and two:
“Sometime” as an adjective means “occasional” or “here today/gone tomorrow.”
…He is a sometime friend.
“Some time” is an adjective and noun combination. “Time” is the noun. There are times when it has to be two words because the grammar calls for a noun.
Here the word “time” is the main word in the expression. We don’t say, “Ago I saw him.”
…some time ago…
…some time back…
Here it is the object of the preposition, which always has to be a noun.
…for some time…
…in some time…
…at some time…
Otherwise, “some time” is two words when it means “a period of time.” Often, with this meaning, the word “some” can be left out.
…I have some time tomorrow.
…We spent some time discussing it.
…There will be some time for that later today.
“Sometime” is an adverb and means at “a point in time.” “Time” doesn’t work by itself here. And here the whole word can be left out.
…I will see you sometime this afternoon.
…We met sometime last week.
…She will be here sometime later.