En lo que = hasta que?

En lo que = hasta que?
 

Acabo de escuchar esta oración: "Prefiero pasar un rato contigo en lo que Rogelio llega." ¿"En lo que" puede significar "hasta que"? Pero, si es así, ¿por qué no es "en lo que Rogelio llegue"? Estoy confundido.

The whole clauses mean approximately the same, but in a different way:

"hasta que Rogelio llegue" defines the lapse by naming the condition that defines its end. (The lapse is defined by the fact that makes it to come to an end)

"en lo que Rogelio llega" names the whole lapse that ends with the same condition. (The lapse is defined by the duration of an impending arrival of Rogelio)

This second case, using indicative, generally supposes that Rogelio's trip has started and he's in his way. With the first one we don't know for sure what is Rogelio doing now.

1) "Voy en camino." "Ok, nos esperaremos en lo que llegas."
2) "No sé cuando me voy a poder ir." "Ok, nos esperaremos hasta que llegues."

Todo correcto? Que tal esto:

3) "Nos esperaremos en lo que el viene."
4) "Dormí en el carro en lo que viajamos."
5) "Hablemos en lo que la cena esta lista."

Good job! :thumbsup:

You got the concept and the forms right; I would just like to make a little remark:
"Nos esperaremos" is used rather for spoken language, and it's a little informal. A less colloquial sentence would override the pronominal: "esperaremos en lo que llegas/hasta que llegues"; or make an emphasis on the other person: "te esperamos/esperaremos en lo que llegas/hasta que llegues".


Some spelling corrections below:

Not sure what you are trying to say with "nos esperaremos" (it means "we'll wait for each other"). It could be "(te) esperaremos mientras llegas" o "haremos otra cosa en lo que llegas".

3)4)and 5) are unusual, and even abnormal, as they have simpler versions:

Nos entretendremos mientras llega.
Dormí en el auto durante el viaje.
Hablemos mientras se cocina la cena.

Use that structure with caution as it is not very common and not all verbs are suitable for it. "Está lista" is not a good choice, though you may wonder why "llegar" -something that happens in a sudden- can be one. I think verbs related to movement or stages in a trip are right for this structure:

"Pondré trodo en orden en lo que él va y vuelve del banco"

or some fixed expressions:

"Estará listo en menos que canta un gallo"

but little else.