Que and Lo Que

Que and Lo Que
 

Thought I understood this until I got these results using several translators (Microsoft, Google and Alexa). For “I know what happened” all of them used Lo Que; but for “I do not know what happened”, all used Que only. And for “I know what to do”, I was getting only Que for both the affirmative and negative. I thought all of these examples would be Lo Que. Ayudame por favor.

lo que = that which (the thing that)
que = that (which, who)
qué = what

Using lo que indicates that something particular is being referenced, including a topic, event, or idea (abstract).

Machine translations can seldom produce the correct idea in every instance, because the machine has no idea about what meaning you want to convey.

The sentences you mentioned can contain either lo que or qué, depending on the meaning you want to convey.
You can't have que in the sentences.

Thanks Rusty. Also, thanks for referencing the accent mark. I need to pay more attention to those.

You're welcome.

The accent mark (tilde) is very important. In case you weren't aware, there's an 'Accents' drop-down menu just above where you type here. Use it to select all the special characters you'll need to write in Spanish.

I actually meant that qué (what) should have been used, in addition to lo que, remembering what is meant.