Nous relevons l’index de consommation lorsque l’auto-relevé arrive.

Here relevons comes from the verb relever.

In this context, relever means to record, take down, or read a meter value. So nous relevons means we record or we take the reading.

Be careful: relever can have other meanings in French too, such as to raise, to pick up, or in reflexive form se relever, to get up again. Here it is the utility/meter-reading meaning.

Because this is not the reflexive verb.

• nous relevons = we record / we take down
• nous nous relevons = we get up again / we stand back up

So although the verb looks familiar, the meaning changes depending on whether it is reflexive.

In this sentence, relever takes a direct object: l’index de consommation.

In this kind of administrative or utility context, index usually means the meter reading, meaning the number shown on a gas, electricity, or water meter.

So l’index de consommation is basically:

• the consumption reading
• the meter reading
• the consumption index/value shown on the meter

This is a specialized use of index. It does not mean the index of a book here.

Auto-relevé means a self-reading: the customer reads the meter themselves and sends the number to the company.

So:

• relevé = a reading / a recorded value
• auto-relevé = a self-reported meter reading

The hyphen is normal here. It is a fixed compound noun.

Because both nouns are masculine singular and begin with a vowel sound:

• le index becomes l’index
• le auto-relevé becomes l’auto-relevé

This is called elision. French often drops the vowel of le or la before a vowel or mute h.

So:

• le + index → l’index
• le + auto-relevé → l’auto-relevé

Because de consommation is being used as a descriptive complement, similar to of consumption or consumption-related.

French often uses de + noun without an article in this kind of fixed expression.

So index de consommation means something like:

• consumption index
• consumption reading

If you said de la consommation, it would sound more like of the consumption, which is less natural here.

Both lorsque and quand can mean when.

In this sentence, lorsque sounds a bit more formal or administrative, which fits the context well. You often see it in writing, instructions, official messages, and customer-service language.

So:

• lorsque = when (slightly more formal)
• quand = when (more common in everyday speech)

In many situations, you could replace lorsque with quand without changing the basic meaning.

Because the sentence describes a general procedure or habitual action, not one single event.

• Nous relevons... = We record...
• l’auto-relevé arrive = the self-reading arrives

French uses the present tense for things that happen regularly or as part of a process. English often does the same:

• We record the meter reading when the self-reading arrives.

So this is not necessarily talking about right now. It is more like this is what we do whenever that happens.

Because the subject is singular: l’auto-relevé.

So the verb must match that subject:

• l’auto-relevé arrive = the self-reading arrives
• les auto-relevés arrivent = the self-readings arrive

French verbs must agree with their subject in number and person, just as English distinguishes between arrive and arrives.

Yes. The structure is very normal French:

• Nous relevons l’index de consommation = main clause
• lorsque l’auto-relevé arrive = time clause introduced by lorsque

So the pattern is:

subject + verb + object + time clause

You could also put the time clause first:

Lorsque l’auto-relevé arrive, nous relevons l’index de consommation.

That would also be correct. It just changes the emphasis slightly.

Yes, literally it means we, but in this kind of sentence it often refers to the company, the service provider, or the organization speaking to the customer.

So nous may not mean a small group of people physically doing the action together. It can mean:

• we, the company
• we, the utility provider
• we, the service team

This is very common in French business and administrative writing.

Not exactly. The French pronunciation is different.

A simple approximation is:

• index ≈ in-deks, but with a French nasal vowel at the start

Important differences from English:

• the first vowel is nasal
• the stress pattern is more even
• the final x is pronounced

So even though the spelling looks familiar, the pronunciation is distinctly French.