Hola Emanuel
El lunes que viene and el próximo lunes are synonymous and interchangeable, for "next Monday", but notice that I am saying "el próximo lunes" not "el lunes próximo". If I used "el lunes próximo" this would normally mean that I am referring to the Monday that comes after some date that has been mentioned. See this mini dialogue:
- ¿Entonces tienes tu examen de inglés el mismo día que tu examen de alemán?
- No. El examen de alemán lo tengo el lunes próximo.
The second person is saying that the German exam is the Monday "after he has the English exam".
I hope this helps,
Inma
